Fire damage protected offshore oil producing rig

ABSTRACT

A method and means for protecting the structural integrity of offshore oil and gas producing rigs from damage due to blowout fires. The invention includes vertical, tubular members which form passageways for water and are in fluid communication with cross members providing lateral support. The water may be pumped either through an inlet depending into the water and positioned between the surrounding tubular members and then forced throughout the tubular members by a pump that is supported on a lower platform above or below the lower surface of the water, alternatively an independent vessel may be connected to one or more of the tubular members by means of a subsea line to circulate water from the sea through each of the tubular and cross members. Nozzles may be positioned on the tubular members pointing inwardly and downwardly toward the wellhead to provide a spray that may be directed into a flame and also used to direct a cooling stream to anyone of the platforms.

[ Nov. 13, 1973 ABSTRACT v A method and means for protecting the structural in- ,Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Y. Mar Attorney-Thomas B. Van Poole et a1.

tegrity of offshore oil and gas producing rigs from damage due to blowout fires. The invention includes vertical, tubular members which form passageways for water and are in fluid communication with cross members providing lateral support. The water may be pumped either through an inlet depending into the water and positioned between the surrounding tubular members and then forced throughout the tubular members by a pump that is supported on a lower platform above or below the lower surface of the water, alternatively an independent vessel may be connected to one or more of the tubular members by means of a subsea line to circulate water from the sea through each of the tubular and cross members. Nozzles may OR 3 977 l. 9 604 SR 0 United States Patent [191 Norman et a1.

[ FIRE DAMAGE PROTECTED OFFSHORE OIL PRODUCING RIG {76] lnventors: Robert M. Norman; Richard H.

Barron, both of Rt. No. 3, Box 988 B, Morgan City, La. 70380 [22] Filed: Apr. 6, 1972 [21] Appl. No.: 241,624

[52] 11.8. 169/1 A, 166/5, 169/13 [51] Int. A62c 35/40 [58] Field'of Search.............,.......... 169/1 A, 2 R, 5, 169/13; 239/208, 209; 166/5, 53, 64, 90

[56] References Cited UNITED STATES PATENTS I 11/1971 Wiseman, Jr.

1 9 3 be positioned on the tubular members pointing in- 239/209 UX wardly and downwardly toward the wellhead to pro- 239/209 UX vide a spray that may be directed into a flame and also 239/209 X used to direct a cooling stream to anyone ofv the plat- 169/2 RX for,

Multin................ Lillibridge et al.

n a MB 975 7/1950 Thompson..............................

13 Claims, 1 Drawing Figure ll illl Patented Nov. 13, 1973 m 440x14. Mp

lriltllfl FIRE DAMAGE PROTECTED OFFSHORE OIL PRODUCING RIG BACKGROUND OF THE INVENTION This invention relates generally to offshore oil producing rigs and more particularly the present invention is concerned with means to-prevent heat or fire damage to such a rig from a blowout fire.

There has been considerable publicity in recent months concerning blowout fires that erupt on offshore oil or gas producing rigs. These fires occurring in oil production rigs have produced outcrys in both public and government groups that have caused. grave concern to the oil industry. While special storm chokes are produced in the oil producing wells and are designed to shut off the flow from each zone in the event that the wellhead is damaged, it has become apparent that some of the procedures have not worked satisfactorily to shut off the fuel flow. The fires with uninterrupted feed then continue to rage out of control. p

The prime concern of the government and public is the pollution damage to the sea from the spilling of any of the crude oil. Thus, while it is possible usually to put the fire out, to'do so would mean that the oil is spilled into the sea causing irreparable damage. To prevent pollution of the sea, blowout fires are generally permitted to continue to burn, thus preventing the sea pollution while highly specialized technical personnel attempt to shut off the flow of oil to the source of the fire.-

This method has generally'been successful in eventually extinguishing the fire, however, such fires have been known to burn for very long periods of time. While every consideration must be given to the environment, sight cannot be lost of the fact that permitting the fire to burn totally destroys the platform and supporting members forming therig. At best,all that may remain is a portion of the afterdeck of the top-most platform. The heat from the fire is found to so seriously damage and deform the verticaland horizontal supports that the entire rig must be rebuilt.

OBJECTS OF THE INVENTION It is, therefore, the principle object of the present invention to provide a method and means for protecting the structural integrity of an offshore oil producing rig from damage due to the blowout fire.

A further object of the present invention is to provide for the support of the rig with hollow interconnected tubular members and hollow cross members which may be supplied with water to maintain a reduced temperature in these members during the fire and thus prevent deformation by high heat due to the fire.

A further object of the present invention is the method and means of spraying water into the interior of the rig toward the wellhead and to supply this water from the tubular members.

This invention also has the further object, the provision of method and means for supplying water to the structural members, whereby such water may be distributed throughout the structural members for reducing and lowering the temperature during blowout fire.

A further object of the present invention is the provision of method and means for supplying water to the hollow structural members either from a pump supported on a subplatform above the water level or from a vessel connected to the members by a subsea connection.

These and other objects of the present invention will be readily apparent from a consideration of the drawing in which there is shown the apparatus of the present invention in perspective and partly broken away to illustrate the hollow, vertical and cross members and the location of the subsea connection.

SUMMARY OF THE INVENTION This invention includes a method and means for protecting the structural integrity of offshore oil producing rigs from damage during to blowout fires. The inven- 'tion includes vertical, tubular members which form passageways for water and are in fluid communication with hollow cross members which provide lateral support. The water may be received either through an inlet depending into the water and positioned between the surrounding tubular members and then forced thoughout the tubular members by a pump that is supported on a lower platform above or below the lower surface ofthe water. Alternatively, an independent vessel may be connected to one or more of the tubular members by means of a subsea line to circulate water from the sea through each of the tubular and cross members. Nozzles may be positioned on the tubular members pointing inwardly and downwardly toward the wellhead to provide a spray that may be directed into a flame and also used to direct a cooling stream to anyone of the platforms.

DESCRIPTION OF PREFERRED EMBODIMENT In the drawing, there is depicted generally the offshore oil producing rig which surrounds the conventional oil well (not shown) and the usual wellhead (not shown).

The rig is composed of at least 4 substantially vertical tubular members 12 which provide vertical support for the structure of the rig. The tubular members are in a conventional fashion each secured to the bottom of the sea by extension 14. The tubular members 12 extend above the surface of the sea and are supported in their upright position by laterally extending cross members 16 which may be horizontal as shown at 18 or angled as at 20. All of the cross members are connected to the tubular members 12 in any suitable leak tight manner as by welding such as shown at 22 and are in fluid communication with each other and with the tubular members 12, as may be seen in the partly broken away section at 24.

All of the tubular members 12 and the cross members 16 are of sizes and materials in structural rigidity sufficient to support the platform P and do not form a part of this invention. It is important, however, both the tubular members and the cross members 12 and 16, respectively, provide good passageways and are conducting water flow throughout all the structural members.

The platform P is a conventional platform used for rotating wing aircraft landings and various equipment for maintenance and repair of the platform as well as, if necessary, crew quarters and other support facilities which are not shown and form no part of the present invention.

Positioned at any suitable location preferably at the upper portions of each of the tubular members 12 are a plurality of spray nozzles 26 which are in fluid communication with the tubular member 12 and are preferably, though not necessarily, directed inwardly and downwardly toward the wellhead which normally would be expected to be the source of the flame and heat. At least one or more nozzles 26 could also be directed to spray upwardly on the underneath side of the platform P to protect such platform from the ravages of heat. It is also contemplated that suitable: conventional valve mechanism (not shown) may be used to control the flow and completely shutoff the nozzles 26. The nozzles may be positioned vertically along the tubular member 12 but also if desired, may be positioned on the cross members 16. Again, suitable valve mechanism may be operated from any suitable location or under the sea at a position along the extensions 14, if desired, in order to avoid danger from the heat of the blowout fire, should one occur.

Each tubular member is provided with a suitable flow. control means as shown at 28 to prevent the flow of water in a downward direction below the sea level. Also, suitable flow control devices (not shown) may be positioned to distribute the water flow at intersecting points of the tubular members such as, for instance, points 30. The flow control mechanism may be manually operated or power controlled in any suitable manner, the controls of which are not shown and form no part of this invention may be placed anywhere on the rig or below the surface S. i

To supply the water to the tubular members, subplatform 32 is positioned preferably just above the surface of the water and may be formed from elongated plate members 34 or other horizontal structural supporting members which are conveniently supported by cross members 36 which may be similar to cross members 18 and may be welded thereto. Supported on subplatform 32, may be an automatic pump 38 which may be of centrifugal or displacement type and either operated by fuel or steam. Fuel line 40 for operating motor 41 may be projected down as shown to a source of fuel held below the surface of the water for obvious safety reasons. The pump drive line may operate to direct the flow of water from inlet 42 through the pump means 38, operated by the motor 41, through outlet 46 into anyone of the tubular or cross members 12, 18 or 20. If desired, the spray nozzles 26 may be closedand the water flow circulated throughout all the tubular and cross members and the inlet 42 connected to member 36 in a manner not shown. It would be desirable in this case to provide a one-way valve and a tubular member between the inlet from member 36 and the outlet into adjacent tubular member.

As an alternative approach, the motor and pump units may be omitted and the entire motor power for the flow of water provided by a vessel holding alongside which would tap into the fluid system of the tubular members 12 through pipeline 48 at subsea line connection 50. A plurality of such pipelines 48 may be positioned around the rig to tap into appropriate locations on the tubular members. One-way valve 52 is provided to control the flow of the liquid. It is possible that the pump 38 and the pipeline 48 connected to the vessel alongside may be used at the same time to provide sufficient water pressure though usually either one or the other would be adequate to provide sufficient flow of water throughout the structure.

It may readily be seen that the foregoing apparatus when in operation after the blowout fire will, with water circulating throughout all of the tubular member, maintain a temperature of the tubular members well below the heat deformation temperature and will maintain the structural integrity of the rig. The operation of the pump 38 may be automatically maintained by an appropriate heat sensor 54 which operates the motor 41 upon receiving the signal that the temperature in the area around the rig'is above a present temperature. Other such sensors may be useful as control means for the flow through the nozzles.

I claim:

1. A method of protecting the structural integrity of an offshore oil producing rig from damage during a blowout fire comprising:

supporting said rig with interconnected tubular members, conducting water through said members throughout said rig to reduce the temperature of said members during a blowout fire and prevent deformation due to heat.

2. The method of claim 1 including supplying said water from the sea.

3. The method of claim 1 including spraying said water into the interior of said rig.

4. The method of claim 1 including supplying said water from a vessel and connecting said vessel to said members by a subsea inlet.

5. The method of claim 2 including pumping said water from a source of power located adjacent the surface of the sea.

6. An offshore oil producing rig protected from damage during a blowout fire comprising:

at least four substantially vertical tubular members extending above the sea level and anchored below the sea level into the bottom to provide support for said rig,

a plurality of hollow cross members extending between and in fluid communication with said vertical tubular members,

inlet means extending below the surface of said sea and in fluid communication with said members extending above said sea level,

power means in fluid communication with said inlet means to pump water throughout said cross members and tubular members to reduce the temperature of said members during a blowout fire in said rig and prevent heat deformation of said members and said rig.

7. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members.

8. The rig of claim,7 including said inlet means being a separate vertical member connected to the inlet side of said pump and extending into the sea between said tubular members.

6. The rig of claim 6 including said inlet means being fluidly connected to said vertical member above said sea surface.

10. The rig of claim 6 including a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire.

11. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members and a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire.

12. The rig of claim 6 including 13. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members,

said inlet means being fluidly connected to said vertical member above said sea surface, and

a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire. 

1. A method of protecting the structural integrity of an offshore oil producing rig from damage during a blowout fire comprising: supporting said rig with interconnected tubular members, conducting water through said members throughout said rig to reduce the temperature of said members during a blowout fire and prevent deformation due to heat.
 2. The method of claim 1 including supplying said water from the sea.
 3. The method of claim 1 including spraying said water into the interior of said rig.
 4. The method of claim 1 including supplying said water from a vessel and connecting said vessel to said members by a subsea inlet.
 5. The method of claim 2 including pumping said water from a source of power located adjacent the surface of the sea.
 6. An offshore oil producing rig protected from damage during a blowout fire comprising: at least four substantially vertical tubular members extending above the sea level and anchored below the sea level into the bottom to provide support for said rig, a plurality of hollow cross members extending between and in fluid communication with said vertical tubular members, inlet means extending below the surface of said sea and in fluid communication with said members extending above said sea level, power means in fluid communication with said inlet means to pump water throughout said cross members and tubular members to reduce the temperature of said members during a blowout fire in said rig and prevent heat deformation of said members and said rig.
 7. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members.
 8. The rig of claim 7 including said inlet means being a separate vertical member connected to the inlet side of said pump and extending into the sea between said tubular members.
 9. The rig of claim 6 including said inlet means being fluidly connected to said vertical member above said sea surface.
 10. The rig of claim 6 including a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire.
 11. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members and a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire.
 12. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members, said inlet means being a separate vertical member connected to the inlet side of said pump and extending into the sea between said tubular members, and a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire.
 13. The rig of claim 6 including said power means consisting of a pump supported on said rig adjacent said tubular members, said inlet means being fluidly connected to said vertical member above said sea surface, and a plurality of spray nozzles fluidly connected to said members, said nozzles being directed inwardly into the interior of said rig and adapted to spray water onto the source of the fire. 